Scattering-based nonlinear macromodels of high-speed differential drivers

Abstract

This paper introduces a scattering-based nonlinear macromodeling framework for high-speed differential drivers. Using an industrial test case, we show that the proposed scattering formulation enables more accurate and robust model identification with respect to standard voltage-current representations. The combination of proposed driver models with a Waveform Relaxation solver allows accurate and efficient transient channel simulation, including nonlinear and dynamic termination effects.

Macromodel-Based Iterative Solvers for Simulation of High-Speed Links With Nonlinear Terminations

“…As discussed in [63], common and differential incident waves form the input set of choice for the scattering-based Mπlog model for differential drivers, which consists of the following:…”

“…Also in this case, the estimation process of (22) is standard and follows the same guidelines that apply for the identification of voltage-current models [6]. See [63] for more details on the peculiarities of scattering-based models.…”

“…The reference device is the transistor-level schematic coded for the Spectre simulator. More details on this driver and its Mπlog macromodeling process can be found in [63].…”

“…A novel and more application-oriented implementation is instead based on behavioral macromodels of drivers and receivers. In particular, we adopt a new scatteringbased formulation extending the results of [63], by suitably modifying the Mπlog macromodel format [6], [7], to obtain termination equations that are compatible with our simulation setup. We show excellent convergence and performance when applying the solver to various industrial channels from [29], driven by production-level driver models.…”

Enhanced macromodels of high-speed low-power differential drivers

“…Specific emphasis is placed on the effects of internal voltage regulators, that unavoidably introduce a rich dynamic behavior on the output commonmode voltage. This behavior can be hardly reproduced by the existing state-of-the-art modeling solutions (e.g., IBIS [1] or Mπlog [3]- [5]). To overcome the above limitation, enhanced models based on the Mπlog class are presented and demonstrated on a high-speed driver for Gbps-range data transfer, implemented in a leading-edge silicon CMOS technology.…”